Multi-drum washing machine and drainage control method

ABSTRACT

A multi-drum washing machine drainage control method, the multi-drum washing machine at least comprising a first washing drum and a second washing drum; the method comprising: when the first washing drum reaches a drainage process, determining whether the second washing drum is draining; if yes, then the first washing drum waits for the second washing drum to finish draining before starting to drain; and if not, then determining whether the first washing drum waits for the second washing drum to finish draining before starting to drain. Alternatively, when the first washing drum reaches the drainage process, determining whether the second washing drum is draining or dehydrating; if yes, then the first washing drum waits for the second washing drum to finish draining before starting to drain; and if not, then determining whether the first washing drum waits for the second washing drum to finish draining before starting to drain.

FIELD OF THE INVENTION

The present disclosure relates to a field of washing, more particularly,to a drainage control method of a multi-drum washing machine.

BACKGROUND OF THE INVENTION

At present, most of the drum washing machines on sale in the market haveonly one washing drum. With the strengthening of people's healthawareness, more and more users need to separate the different types ofclothing to wash or to wash a small amount of clothing in a timelymanner.

With the improvement of people's quality of life, people's healthawareness has gradually increased, especially in the family clothingwashing, more and more people wash clothes separately. If using theexisting washing machine to take multiple laundry, the laundry time ishard to meet the requirements of the users. If buying two or morewashing machines to wash separately at the same time, it will not onlybring a great waste of energy and water resources but also occupy alarge space, which is not suitable for home use. Therefore, the use ofmulti-drum washing machine will meet the needs above and solve theproblem of energy, water and space waste.

A patent No. 201010117002.0 discloses a control method of a washingmachine which comprises a first washing drum and a second washing drum.The method includes steps: receiving a first operation instruction forrequiring a water supply or a drainage program to be executed in saidfirst washing drum; determining whether or not a same operationinstruction is being executed in said second washing drum. When the sameoperation instruction is being executed in the said second washing drum,it is determined that the first operation instruction cannot beexecuted. When the same operation instructions of the water supply andthe drainage program are input at the same time in said first washingdrum and said second washing drum, it is determined that said firstwashing drum or said second washing machine has a shorter remainingwashing time. And the water supply or the drainage program is preferablyexecuted in the washing drum having a relatively shorter remainingwashing time.

A double-drum washing machine has a high center of gravity, which isunstable, so it has a higher requirement to vibration. However, thelarger the overall weight of the washing machine, the smaller thevibration. During the dehydration process, the high-speed rotation ofthe drum will certainly bring vibration, and the drum with a highercenter of gravity will produce larger vibration and noise which bringsunnecessary trouble to the daily life. Sometime, one washing drum isdraining while the other washing drum is dehydrating, if draining wateraway, the vibration will increase. The water can be used as acounterweight if the water is not drained away. However, the situationis usually not that a washing drum is draining when the other washingdrum is dehydrating. So it needs to be determined whether to wait theother washing drum drains.

In the view of foregoing, the present disclosure is proposed.

SUMMARY OF THE INVENTION

An object of the present disclosure is to overcome the shortcomings ofthe prior art, and provides a drainage control method of a multi-drumwashing machine to reduce the vibration during the dehydration process.

In order to achieve such object, the technical scheme is adopted by thepresent disclosure as follows: a drainage control method of a multi-drumwashing machine which at least comprises a first washing drum and asecond washing drum. When the first washing drum reaches a drainageprocess, it is determined whether or not the second washing drum is in adehydration process at this time. If the second washing drum is in thedehydration process, the first washing drum waits until the dehydrationprocess of the second washing drum is completed, and then drains.

If the second washing drum is not in the dehydration process at thistime, it is determined whether or not to wait until the dehydrationprocess of the second washing drum is completed, and then to drain.

To determine whether or not to wait until the dehydration process of thesecond washing drum is completed, and then to drain: a time for reachingthe dehydration process of the second washing drum is T₃₂, a time takenfor the second washing drum to dehydrate is T₃₃, and an allowablewaiting time T₃ is set. If T₃₂+T₃₃<T₃, the first washing drum waitsuntil the dehydration process of the second washing drum is completed,and then drains. Otherwise, the water in the first washing drum isdrained directly.

When the first washing is about to drain, it is determined whether ornot the second washing drum is draining at this time. If the secondwashing drum is draining at the time, the first washing drum waits untilthe drainage of the second washing drum is completed, and drains.Otherwise, the water of the first washing drum is drained directly.

When the first washing drum reaches the drainage process, it is compareda time T₁₂ for reaching a water supply process of the second washingdrum and a time T₁₁ for reaching a next drainage process of the firstwashing drum. If T₁₂<T₁₁, the first washing drum waits until the secondwashing drum supplies water. If T₁₂≧T₁₁, the water in the first washingdrum is drained directly.

It is determined whether or not the water in the first washing drum canbe reused before comparing the time T₁₂ for reaching the water supplyprocess of the second washing drum and the time T₁₁ for reaching thenext drainage process of the first washing drum. If no, the water in thefirst washing drum is drained directly. If yes, it is compared the timeT₁₂ for reaching the water supply process of the second washing drum andthe time T₁₁ for reaching the next drainage process of the first washingdrum.

Or, it is determined whether or not the water in the first washing drumcan be reused when the first washing drum waits until the second washingdrum supplies water. If no, the water in the first washing drum isdrained directly. If yes, the water in the first washing drum is drainedinto the second washing drum for reusing.

If the second washing drum is supplying water when the first washingdrum reaches the drainage process, the time T₁₂ for reaching the watersupply process of the second washing drum is 0, and no need to wait.

Set an allowable waiting time T₁, if T₁₂<T₁, the first washing drumwaits until the second washing drum supplies water. If T₁₂≧T₁, the waterin the first washing drum is drained directly.

When the first washing drum reaches the drainage process, it isdetermined whether or not the process which the second washing drum isin progress or is about to be performed is a water supply for a lastrinse. If yes, the water in the first washing drum is drained directly.If no, it is continued to be determined whether or not the water in thefirst washing drum can be reused.

When the second washing drum reaches the drainage process, it isdetermined whether or not the first washing drum is in the dehydrationprocess at this time. If it is in the dehydration process, the secondwashing drum waits until the dehydration process of the first washingdrum is completed, and then drains. If the first washing drum is not inthe dehydration process at this time, it is determined whether or not towait until the dehydration process of the first washing drum iscompleted, and then drains.

When the first washing drum reaches the drainage process, it isdetermined whether or not the second washing drum is operating at thistime. If yes, it is determined whether or not the second washing drum isin the dehydration process or is about to execute the dehydrationprocess. If no, the first washing drum directly executes the drainageprocess.

A drainage control method of a multi-drum washing machine is provided,and the multi-drum washing machine at least comprises a first washingdrum and a second washing drum. When the first washing drum reaches adrainage process, it is determined whether or not the second washingdrum is in a drainage process or in a dehydration process. If the secondwashing drum is in the drainage process or in the dehydration process,the first washing drum waits until the dehydration process of the secondwashing drum is completed, and then drains. If the second washing drumis not in the drainage process or in the dehydration process, it isdetermined whether or not the first washing drum needs to wait until thedehydration process of the second washing drum is completed, and thendrains.

To determine whether or not the first washing drum needs to wait untilthe dehydration process of the second washing drum is completed, andthen drains: a time for reaching the drainage process of the secondwashing drum is T₃₁, a time taken for the second washing drum to drainis T₃₄, a time taken for the second washing drum to dehydrate is T₃₃,and a time for reaching a next drainage process of the first washingdrum is T₅. If T₅<T₃₁+T₃₄, the water in the first washing drum isdrained directly. Otherwise, it is continued to be determined whether ornot the first washing drum needs to wait until the dehydration processof the second washing drum is completed, and then drains.

To determine whether or not the first washing drum needs to wait untilthe dehydration process of the second washing drum is completed, andthen drains: a time for reaching the drainage process of the secondwashing drum is T₃₁, a time taken for the second washing drum to drainis T₃₄, a time taken for the second washing drum to dehydrate is T₃₃. Anallowable waiting time T₃ is set. If T₃₁+T₃₄+T₃₃<T₃, the first washingdrum waits until the dehydration process of the second washing drum iscompleted, and then drains. Otherwise, the water in the first washingdrum is drained directly.

When the first washing drum reaches the drainage process, it is firstlydetermined whether or not the second washing drum is operating. If no,the first washing drum directly executes the drainage process. If yes,it is continued to be determined whether or not the second washing drumis in the drainage process or in the dehydration process.

If it is determined the first washing drums waits until the dehydrationprocess of the second washing drum is completed, it is determinedwhether or not the second washing drum needs to supply water after thedehydration process is completed. If water supply is not required, thewater in the first washing drum is drained directly. If water supply isrequired, it is determined whether or not the water in the first washingdrum can be reused. If the water can be reused, the water in the firstwashing drum is drained into the second washing drum.

When the first washing drum reaches the drainage process and if thesecond washing drum is supplying water, it is determined whether or notthe water in the first washing drum can be reused. If the water can bereused, the water in the first washing drum is drained into the secondwashing drum.

If the process which second washing drum is in or is about to perform isa water supply for a last rinse, the water in the first washing drumcannot be reused.

If the first washing drum is in the drainage of the last rinse, thewater in the first washing drum cannot be reused.

The water in the first washing drum cannot be reused, if the firstwashing drum is in a washing process when it drains, and the secondwashing drum is in a rinse process when it supplies water; or if thefirst and second washing drums are both in the washing process when thefirst washing drum drains and the second washing drum supplies water,and washing times of the first washing drum is less than washing timesof the second washing drum; or if the first and second washing drums areboth in the rinse process when the first washing drum drains and thesecond washing drum supplies water, and rinsing times of the firstwashing drum is less than rinsing times of the second washing drum; orif a turbidity of the water in the first washing drum exceeds a setvalue.

When the second washing drum reaches the drainage process, it isdetermined whether or not the first washing drum is in the drainageprocess or in the dehydration process at this time. If the first washingdrum is in the drainage process or in the dehydration process, thesecond washing drum waits until the dehydration of the first washingdrum is completed, and then drains. If the first washing drum is not inthe drainage process or in the dehydration process, it is determinedwhether or not the second washing drum needs to wait until thedehydration process of the first washing drum is completed, and thendrains.

By adopting the technical scheme of the present disclosure, it bringsthe following benefits:

1. When one washing drum of the washing machine of the presentdisclosure drains and if the other washing drum is in the dehydrationprocess or will be in the dehydration process in a certain time, thefirst washing drum will not drain to increase the weight of the washingmachine to reduce vibration. When one washing drum reaches drainageprocess and if the other washing drum is in the drainage or dehydrationprocess, or will be in the drainage or dehydration process in a certaintime, the first washing drum will not drain to increase the weight ofthe washing machine. It plays a role in increasing the counterweight toachieve vibration absorption effect when the second washing drum isdehydrating.

2. The present disclosure increases the determination process of waitingfor drainage after dehydration, and reasonably arranges the workingprocess of the two washing drums to realize the vibration reductioneffect to the maximum extent.

3. The present disclosure determines whether or not one washing drumdrains water to the other washing drum for water reuse according to thedrainage waiting time when it reaches the drainage process. The presentdisclosure has a simple determination and control logic and has a higherstability in the actual washing process. At the same time, it makes fullreuse of washing water and has a high practical value and is moreeffective to promote the application.

4. The present disclosure accurately determines that the water cannot bereused and ensures the washing effect.

The following is further described in details with embodiments of thepresent disclosure.

BRIEF DESCRIPTION OF THE INVENTION

FIG. 1: A structural diagram of a double-drum washing machine of thepresent disclosure

FIG. 2: A flow chart of a control method of the present disclosure

FIG. 3: A flow chart of a control method of an embodiment of the presentdisclosure

FIG. 4: A flow chart of a control method of an embodiment of the presentdisclosure

FIG. 5: A flow chart of a control method of an embodiment of the presentdisclosure

FIG. 6: A flow chart of a control method of an embodiment of the presentdisclosure

Wherein: 1. A first washing drum, 2. A second washing drum.

DETAILED DESCRIPTION OF THE INVENTION

As shown in FIG. 1, a double-drum washing machine which provides with afirst washing drum 1 and a second washing drum 2 capable ofindependently performing washing steps. The first washing drum 1 and thesecond washing drum 2 can respectively and independently execute a watersupply process, a washing process, a drainage process, a rinse process,a dehydration process in turn for clothes, which is to achieve thepurpose of washing clothes. Preferably, the first washing drum and thesecond washing drum may also be separately provided with a drying meansfor executing a drying process after the dehydration process to achievethe purpose of drying the clothes in the first washing drum and/or thesecond washing drum. Preferably, the first washing drum is provided witha first heater for heating the washing water therein, and the secondwashing drum is provided with a second heater for heating the washingwater therein. Thus, during the execution of the washing process, thewashing water in the washing drum is subjected to a heat treatment tocontrol the water temperature during the washing process and the washingeffect is improved

In the present disclosure, the first washing drum is communicated withthe second washing drum. The water in the first washing drum can bedrained into the second washing drum for reuse under a certaincondition, and the water in the second washing drum can be drained intothe first washing drum for reuse under a certain condition. If the waterdoesn't meet the condition for reuse, it is drained away through adrainage pipe. Thus, it improves the water utilization and avoids thewaste of water. At the same time, a control process is added to ensurethat the water is only be reused when the water is relatively clean, andensure the washing effect.

Embodiment 1

As shown in FIG. 1, the drainage control method of a multi-drum washingmachine. When the first washing drum reaches the drainage process, it isdetermined whether or not the second washing drum is in a dehydrationprocess. If the second washing drum is in the dehydration process, thefirst washing drum waits until the dehydration process of the secondwashing drum is completed, and then drains. The water in the firstwashing drum plays a role as a counterweight, thus it increases theoverall weight of the washing machine to achieve the effect of vibrationabsorption.

If the second washing drum is not in the dehydration process, it isdetermined whether or not to wait until the dehydration process iscompleted, and drain. Thus can avoid the scenario that the secondwashing drum starts to dehydrate as soon as the first washing drumfinished draining water. Under that scenario the water in the firstwashing drum cannot achieve the effect of vibration absorption,resulting waste.

To determine whether or not to wait until the dehydration process iscompleted, and then drain: a time for reaching the dehydration processof the second washing drum is T₃₂, a time taken for the second washingdrum to dehydrate is T₃₃, an allowable waiting time is T₃. IfT₃₂<T₃−T₃₃, which means it is within a rang of the allowable waitingtime, the first washing drum waits until the dehydration process of thesecond washing drum is completed, and then drains. Otherwise, the waterof the first washing drum is drained directly.

Since draining outlets of the first washing drum and the second washingdrum are connected to a drainage outlet of the washing machine through apipe line, and the entire washing machine has only one drainage outlet.When the two washing drums drain at the same time, it will causecontamination to clothes due to the water reflux caused by the pressuredifference. And the speeds of drainage at the same time and at differenttimes are essentially the same while they share the same drainage pipe,so the first washing drum and the second washing drum cannot drain atthe same time. When the first washing drum is about to drain, it isdetermined whether or not the second washing drum is draining at thistime. If the second washing drum is draining at this time, the firstwashing drum waits until the drainage process of the second washing drumis completed, and then drains. Otherwise, the water in the first washingdrum is drained directly.

In order to reuse the water in the first washing drum, when the firstwashing drum reaches the drainage process, it is determined whether ornot the water in the first washing drum can be reused. If no, the waterin the first washing drum is drained directly. If yes, it is determinedwhether or not the second washing drum is supplying water. If yes, thewater in the first washing drum is drained into the second washing drumto reuse the water; if no, it is determined whether or not the firstwashing drum waits until the second washing drum supplies water.

To determine whether or not the first washing drum waits until thesecond washing drum supplies water: it is compared a time T₁₂ forreaching a water supply process of the second washing drum and a timeT₁₁ for reaching a next drainage process of the first washing drum. IfT₁₂<T₁₁, the first washing drum waits until a start of water supplyprocess of the second washing drum, and the water in the first washingdrum is drained into the second washing drum to reuse the water. IfT₁₂≧T₁₁, the water in the first washing drum is drained directly.

The determination process above may result in a longer waiting time, atthis time, an allowable waiting time T₁, which T₁<T₁₁, can be set. IfT₁₂<T₁, which means that it is within the range of the allowable waitingtime, the first washing drum waits the start of the water supply processof the second washing drum, and the water in the first washing drum isdrained into the second washing drum directly to reuse water. If T₁₂≧T₁,which mean it is beyond the range of the allowable waiting time, and thewater in the first washing drum is drained directly.

When it is determined whether or not the water in the first washing drumcan be reused, the turbidity value or the bubble concentration value ofthe water in the first washing drum is detected. If the turbidity valueor the bubble concentration value of the water is smaller than the setvalue, the water in the first washing drum can be reused. Otherwise thewater in the first washing drum cannot be reused and is drained awaydirectly.

When the first washing drum reaches the drainage process, it isdetermined whether or not the process of which the second washing drumis in progress or is about to be performed is a water supply for a lastrinse. If yes, the water in the first washing drum is drained directly.If no, it is continued determined whether or not the water in the firstwashing drum can be reused.

The first washing drum and the second washing drum are only for the sakeof convenience of the description, regardless of the order of therelationship. It is possible to determine whether or not the firstwashing drum is dehydrating at this time when the second washing drum isdraining. If the first washing drum is dehydrating, the second washingdrum waits after the dehydration of the first washing drum is completed,and drains. The water in the second washing drum plays the role as acounterweight which can increase the overall weight of the washingmachine to achieve the effect of vibration absorption.

If the first washing drum is not draining at this time, it is determinedwhether or not to wait until the dehydration process is completed, anddrain. Thus can avoid the scenario that the first washing drum starts todehydrate as soon as the second washing drum finished draining water.Under that scenario the water in the second washing drum cannot achievethe effect of vibration absorption, resulting waste.

When the first washing drum reaches the drainage process, it isdetermined whether or not the second washing drum is operating at thistime. If yes, it is determined whether or not the second washing drum isin the dehydration process or is about to execute the dehydrationprocess. If no, the first washing drum directly executes the drainageprocess.

As shown in FIG. 2, the control method of the present embodiment is:

1) the first washing drum reaching the drainage process,

2) determining whether or not the second washing drum is operating, ifyes, executing step 3), if no, executing step 8),

3 determining whether or not the second washing drum is draining, if no,executing step 4), if yes, executing step 7),

4) determining whether or not the second washing drum is dehydrating, ifno, executing step 5), if yes, executing step 6),

5) a time for reaching the dehydration process of the second washingdrum being T₃₂, a time taken for the second washing drum to dehydratebeing T₃₃, an allowable waiting time being set to T₃, If T₃₂<T₃−T₃₃,executing step 6), otherwise executing step 8),

6) the first washing drum waiting until the dehydration of the secondwashing drum is completed, executing step 8),

7) the first washing drum waiting until the drainage of the secondwashing drum is completed, executing step 8),

8) the first washing drum draining.

Embodiment 2

As shown in FIG. 5, FIG. 6, the drainage control method of themulti-drum washing machine of the present disclosure. When the firstwashing drum reaches the drainage process, it is determined whether ornot the second washing drum is in a drainage process or in a dehydrationprocess. If the second washing drum is in the drainage process or in thedehydration process, the first washing drum waits until the dehydrationprocess of the second washing drum is completed, and then drains. Whenthe second washing drum is in the dehydration process, the water in thefirst washing drum remaining in the first washing drum, and said waterin the first washing drum plays a role as a counterweight whichincreases the overall weight of the washing machine to achieve theeffect of vibration absorption. That is, the drainage process and thedehydration process of the second washing drum are carried outsuccessively, and the drainage process and the dehydration process arenot interrupted by other processes.

If the second washing drum is not draining or dehydrating at this time,it is determined whether or not the first washing drum waits until thedehydration process of the second washing drum is completed, and thendrains. If the second washing drum is about to dehydrate, the firstwashing drum may wait until the dehydration process is completed, andthen drain. Thus can avoid the scenario that the second washing drumstarts to dehydrate as soon as the first washing drum just finisheddraining water or soon after the first washing drum completes thedrainage. Under that scenario the water in the first washing drum cannotachieve the effect of vibration absorption, resulting waste. When thesecond washing drum is in the dehydration process, the water in thefirst washing drum remain in the first washing drum, said water in thefirst washing drum plays a role as a counterweight which increases theoverall weight of the washing machine to achieve the effect of vibrationabsorption.

To determine whether or not the first washing drum needs to wait untilthe dehydration process of the second washing drum is completed, andthen starts to drain: a time for reaching the drainage process of thesecond washing drum is T₃₁, a time taken for the second washing drum todrain is T₃₄, a time taken for the second washing drum to dehydrate isT₃₃, a time from a next drainage process of the first washing drum isT₅. If T₅<T₃₁+T₃₄, the water in the first washing drum is draineddirectly. The water in the first washing drum is utilized to achieve thevibration absorption of the dehydration when the water in the firstwashing drum is drained next time. Otherwise, the first washing drum isdetermined whether to need to wait until the dehydration process of thesecond washing drum is completed, and then drains. Thus can avoid thefirst washing drum having a too long washing time which caused by thefirst washing drum waiting too long for the completion of thedehydration process of the second washing drum. And if the next drainageprocess of the first washing drum can start before the dehydrationprocess of the second washing drum, the present drainage of the firstwashing drum doesn't have to wait until the dehydration process of thesecond washing drum is completed. The water of the first washing drumplays a role as a counterweight which left in the first washing drum fornext drainage process, and it can increase the overall weight of thewashing machine to achieve vibration absorption.

To determine whether or not to wait until the dehydration process iscompleted, and then drain: a time for reaching the drainage process ofthe second washing drum is T₃₁, a time taken for the second washing drumto drain is T₃₄, a time taken for the second washing drum to dehydrateis T₃₃. An allowable waiting time T₃ is set, if T₃₁+T₃₄+T₃₃<T₃, whichmeans it is within the range of the allowable waiting time, the firstwashing drum waits until the dehydration process of the second washingdrum is completed, and then drains. Otherwise, the water in the firstwashing drum is drained directly. An allowable waiting time is set, andif the drainage waiting time of the first washing drum exceeds the setallowable waiting time, the first washing drum no longer waits until thedehydration process of the second washing drum is completed. It canavoid the first washing drum waiting too long for drainage and cause thewashing time of the first washing drum is too long. Thus can reasonablyarrange the washing processes of the two washing drums.

When the first washing drum reaches the drainage process, it isdetermined whether or not the second washing drum is operating at thistime. If yes, it is determined whether or not the second washing drum isin or is about to execute the dehydration or drainage process. If no,the first washing drum directly executes the drainage process.

Since draining outlets of the first washing drum and the second washingdrum are connected to a drainage outlet of the washing machine through apipe line, and the entire washing machine has only one drainage outlet.When the two washing drums drain at the same time, it will causecontamination to clothes due to the water reflux caused by the pressuredifference. And the speeds of drainage at the same time and at differenttimes are essentially the same while they share the same drainage pipe,so the first washing drum and the second washing drum cannot drain atthe same time. At the same time, the drainage process and thedehydration process of the second washing drum are carried outsuccessively, and the drainage process and the dehydration process arenot interrupted by other processes. When the first washing drum is aboutto drain, it is determined whether or not the second washing drum isdraining at this time. If the second washing drum is draining at thistime, the first washing drum waits until the drainage process of thesecond washing drum is completed, and then drains. Otherwise, the waterin the first washing drum is drained directly.

The dehydration is prone to vibration, especially if a clothing isuneven distribution, it will result in greater vibration and is prone toproduce noise. While the vibration is too large likely to cause theconnection of washing machine parts loose, resulting in failure. Twowashing drums are provided in the present disclosure and when one of thewashing drums is in dehydration process, the water in the other washingdrum can be used to increase the overall weight of the washing machineto reduce vibration. When the first washing drum is about to drain, itis determined whether or not the second washing drum is dehydrating atthis time. If the second washing drum is dehydrating at this time, thefirst washing drum waits until the dehydration process of the secondwashing drum is completed, and then drains, which reduces the vibrationproduced in the dehydration process of the second washing drum.

At the same time, the water in the washing drum can be reused. If it isdetermined the first washing drums waits until the dehydration processof the second washing drum is completed, it is determined whether or notthe second washing drum needs to supply water after the dehydrationprocess is completed. If water supply is not required, the water in thefirst washing drum is drained directly. If water supply is required, itis determined whether or not the water in the first washing drum can bereused. If the water can be reused, the water in the first washing drumis drained into the second washing drum.

When the first washing drum reaches the drainage process and if thesecond washing drum is supplying water, it is determined whether or notthe water in the first washing drum can be reused. If the water can bereused, the water in the first washing drum is drained into the secondwashing drum.

The water in the first washing drum cannot be reused, if the firstwashing drum is in a washing process when it drains and the secondwashing drum is in a rinse process when it supplies water; or if thefirst washing drum drains and the second washing drum are both in thewashing process when the first washing drum drains and the secondwashing drum supplies water, and a number of washing times of the firstwashing drum is less than a number of washing times of the secondwashing drum; or if the first washing drum drains and the second washingdrum are both in the rinse process when the first washing drum drainsand the second washing drum supplies water, and the number of rinsingtimes of the first washing drum is less than the number of rinsing timesof the second washing drum; or if a turbidity of the water in the firstwashing drum exceeds a set value.

When it is determined whether or not the water in the first washing drumcan be reused, the turbidity value or the bubble concentration value ofthe water in the first washing drum is detected. If the turbidity valueor the bubble concentration value of the water is smaller than the setvalue, the water in the first washing drum can be reused. Otherwise thewater in the first washing drum cannot be reused and is drained awaydirectly.

When the first washing drum reaches the drainage process, it isdetermined whether or not the process of which the second washing drumis in progress or is about to be performed is a water supply for a lastrinse. If yes, the water in the first washing drum is drained directly.If no, it is continued to be determined whether or not the water in thefirst washing drum can be reused.

When the first washing drum reaches the drainage process, it isdetermined whether or not the drainage is for the last rinse. If thedrainage is for the last rinse, the water in the first washing drum isdrained directly; if the drainage is not for the last rinse, it isdetermined whether or not the water in the first washing drum can bereused. Since the softener or antivirus agent may be added in the lastrinse, and the second washing drum may not require the process, so thatthe laundry in the second washing drum is prevented from being affected.If the drainage is for the last rinse, the water in the first washingdrum is drained away directly.

The first washing drum and the second washing drum are only for the sakeof convenience of the description, regardless of the order of therelationship. It is possible to determine whether or not the firstwashing drum is draining or dehydrating at this time when the secondwashing drum drains. If the first washing drum is draining ordehydrating, the second washing drum waits until the dehydration of thefirst washing drum is completed, and drains. The water in the secondwashing drum plays the role as a counterweight which can increase theoverall weight of the washing machine to achieve the effect of vibrationabsorption.

If the first washing drum is not draining or dehydrating at this time,it is determined whether or not the second washing drum waits until thedehydration process of the first washing drum is completed, and thendrains. Thus can avoid the scenario that the first washing drum startsto dehydrate as soon as the second washing drum finished draining water.Under that scenario the water in the second washing drum cannot achievethe effect of vibration absorption, resulting waste.

The control method of the present embodiment is:

1) the first washing drum reaching the drainage process;

2) determining whether or not the second washing drum is operating, ifyes, executing step 3), if no, executing step 6);

3) determining whether or not the second washing drum is draining, ifno, executing step 4), if yes, executing step 5);

4) determining whether or not the second washing drum is dehydrating, ifno, executing step 6), if yes, executing step 5);

5) the first washing drum waiting until the dehydration of the secondwashing drum is completed, executing step 6);

6) the first washing drum draining.

Another control method of the present embodiment is:

1) the first washing drum reaching the drainage process;

2) determining whether or not the second washing drum is operating, ifyes, executing step 3), if no, executing step 7);

3) determining whether or not the second washing drum is draining, ifno, executing step 4), if yes, executing step 6);

4) determining whether or not the second washing drum is dehydrating, ifno, executing step 5), if yes, executing step 6);

5) determining a time T₃₁ for reaching the drainage process of thesecond washing drum, a time T₃₄ taken for the second washing drum todrain, a time T₃₃ taken for the second washing drum to dehydrate, a timeT₅ for reaching a next drainage process of the first washing drum, ifT₅<T₃₁+T₃₄, executing step 7), otherwise, executing step 6);

6) the first washing drum waiting until the dehydration of the secondwashing drum is completed, executing step 7);

7) the first washing drum draining.

Another control method of the present embodiment is:

1) the first washing drum reaching the drainage process;

2) determining whether or not the second washing drum is operating, ifyes, executing step 3), if no, executing step 7);

3) determining whether or not the second washing drum is draining, ifno, executing step 4), if yes, executing step 6);

4) determining whether or not the second washing drum is dehydrating, ifno, executing step 5), if yes, executing step 6);

5) determining a time T₃₁ for reaching the drainage process of thesecond washing drum, a time T₃₄ taken for the second washing drum todrain, a time T₃₃ taken for the second washing drum to dehydrate,setting an allowable waiting time T₃, if T₃₁+T₃₄+T₃₃<T₃, executing step6), otherwise, executing step 7);

6) the first washing drum waiting until the dehydration of the secondwashing drum is completed, executing step 7);

7) the first washing drum draining.

Another control method of the present embodiment is:

1) the first washing drum reaching the drainage process;

2) determining whether or not the second washing drum is operating, ifyes, executing step 3), if no, executing step 8);

3) determining whether or not the second washing drum is draining, ifno, executing step 4), if yes, executing step 7);

4) determining whether or not the second washing drum is dehydrating, ifno, executing step 5), if yes, executing step 7);

5) determining a time T₃₁ for reaching the drainage process of thesecond washing drum, a time T₃₄ taken for the second washing drum todrain, a time T₃₃ taken for the second washing drum to dehydrate, a timeT₅ for reaching a next drainage process of the first washing drum ifT₅<T₃₁+T₃₄, executing step 8), otherwise, executing step 6);

6) determining a time T₃₁ for reaching the drainage process of thesecond washing drum, a time T₃₄ taken for the second washing drum todrain, a time T₃₃ taken for the second washing drum to dehydrate settingan allowable waiting time T₃, if T₃₁+T₃₄+T₃₃<T₃, executing step 7),otherwise, executing step 8);

7) the first washing drum waiting until the dehydration of the secondwashing drum is completed, executing step 8);

8) the first washing drum draining.

Another control method of the present embodiment is:

1) the first washing drum reaching the drainage process;

2) determining whether or not the second washing drum is operating, ifyes, executing step 3), if no, executing step 12);

3) determining whether or not the second washing drum is draining, ifno, executing step 4), if yes, executing step 7);

4) determining whether or not the second washing drum is dehydrating, ifno, executing step 5), if yes, executing step 7);

5) determining a time T₃₁ for reaching the drainage process of thesecond washing drum, a time T₃₄ taken for the second washing drum todrain, a time T₃₃ taken for the second washing drum to dehydrate, a timeT₅ for reaching a next drainage process of the first washing drum, ifT₅<T₃₁+T₃₄, executing step 8), otherwise, executing step 6);

6) determining a time T₃₁ for reaching the drainage process of thesecond washing drum, a time T₃₄ taken for the second washing drum todrain, a time T₃₃ taken for the second washing drum to dehydrate,setting an allowable waiting time T₃, if T₃₁+T₃₄+T₃₃<T₃, executing step7), otherwise, executing step 8);

7) the first washing drum waiting until the dehydration of the secondwashing drum is completed, executing step 8);

8) the first washing drum being about to drain;

9) determining whether or not to supply water to the second washingdrum, if yes, executing step 10), if no, executing step 12);

10) determining whether or not the water of the first washing drum canbe reused, if yes, executing step 11), if no, executing step 12);

11) the water in the first washing drum being drained into the secondwashing drum for reuse;

12) the water in the first washing drum being drained away.

Embodiment 3

The control method of the present embodiment increases the process ofreusing the water of the first washing drum. As shown in FIG. 3, in thepresent embodiment, the drainage waiting time is used as thedetermination criterion to determine whether or not to reuse water.According to the drainage waiting time it is determined whether to waitfor the water to be drained to another washing drum for reuse when thedrainage process is reached. The method has a simple judgment andcontrol logic, in the actual washing process, the control stability ishigh. At the same time, it achieves a full reuse of water, and thepractical value is high, which is more effective to promote and apply.

When the first washing drum and the second washing drum are both in theworking state at the same time, the control method of water reuse is asfollows:

A control method of water reuse of a multi-drum washing machine isprovided. The multi-drum washing machine at least comprises a firstwashing drum and a second washing drum. When the first washing drum andthe second washing drum are both in the working state at the same timeand the first washing drum reaches the drainage process, it is compareda time T₁₂ from a water supply process of the second washing drum and atime T₁₁ for reaching a next drainage process of the first washing drum.If T₁₂<T₁₁, the first washing drum waits until a start of water supplyprocess of the second washing drum. If T₁₂≧T₁₁, the water in the firstwashing drum is drained directly.

It is determined whether or not the water in the first washing drum canbe reused before comparing the time T₁₂ for reaching the water supplyprocess of the second washing drum and the time T₁₁ for reaching thenext drainage process of the first washing drum. If no, the water in thefirst washing drum is drained directly. If yes, it is compared the timeT₁₂ for reaching the water supply process of the second washing drum andthe time T₁₁ for reaching the next drainage process of the first washingdrum.

Or, it is determined whether or not the water in the first washing drumcan be reused when the first washing drum waits until the start of thewater supply process of the second washing drum. If no, the water in thefirst washing drum is drained directly. If yes, the water in the firstwashing drum is drained into the second washing drum for reuse.

Specific:

step 1: when the first washing drum reaches the drainage process, it isdetermined whether or not the water in the first washing drum can bereused, if yes, execute step 2, if no, the water in the first washingdrum is drained directly;

step 2: it is compared a time T₁₂ for reaching a water supply process ofthe second washing drum and a time T₁₁ for reaching a next drainageprocess of the first washing drum. If T₁₂<T₁₁, the first washing drumwaits until a start of water supply process of the second washing drumand the water in the first washing drum is drained into the secondwashing drum to reuse. If T₁₂≧T₁₁, the water in the first washing drumis drained directly. By adding the process of the determination ofwhether or not to wait, to a large extent it increases the water reuseprobability of the first washing drum, and more water can be reused.

In step 1, if the second washing drum is supplying water when the firstwashing drum reaches the drainage process, the time T₁₂ for reaching thewater supply process of the second washing drum is 0, and no need towait. The water in the first washing drum is drained into the secondwashing drum to reuse water. It is also possible to first determinewhether or not the second washing drum is currently executing the watersupply process before comparing the time T₁₂ for reaching the watersupply process of the second washing drum and the time T₁₁ for reachinga next drainage process of the first washing drum. If the second washingdrum is not subjected to the water supply process, then it is comparedthe time T₁₂ for reaching the water supply process of the second washingdrum and the time T₁₁ for reaching a next drainage process of the firstwashing drum.

In step 2, an allowable waiting time T₁ is set, which T₁<T₁₁. If T₁₂<T₁,the first washing drum waits until the second washing drum supplieswater and the water in the first washing drum is drained into the secondwashing drum to reuse water. If T₁₂≧T₁, the water in the first washingdrum is drained directly. This step can avoid the first washing drumwaiting too long and reasonably arrange the water reuse under thepremise of ensuring the washing time of the first washing drum. Thuswill not waste too much time of the first washing drum because of onlyconsidering water reuse. If the washing machine determines that thewaiting time is too long and exceeds the set allowable waiting time, thewater in the first washing drum is not reused. The determination makesthe reuse of water more reasonable, optimizing the relationship betweenwaiting time and water reuse.

In step 1, the turbidity value or the bubble concentration value of thewater in the first washing drum is detected. If the turbidity value orthe bubble concentration value of the water is smaller than the setvalue, the water in the first washing drum can be reused. Otherwise thewater in the first washing drum cannot be reused and is drained awaydirectly. Water can be reused when the turbidity value or bubbleconcentration value of the water is within the set range.

In step 1, when the first washing drum reaches the drainage process, itis determined whether or not the process of which the second washingdrum is in progress or is about to be performed is a water supply for alast rinse. If yes, the water in the first washing drum is draineddirectly. If no, it is continued to be determined whether or not thewater in the first washing drum can be reused. Thus to ensure that thewater supplied in the last rinse process is clean water, which ensuresthat the effect of washing clothes after washing.

In step 2, when the water in the first washing drum is drained into thesecond washing drum, it is determined whether or not the second washingdrum executes the water supply process for washing. If yes, the secondwashing drum first supplies water for washing the detergent box. Afterthe completion of water supply for washing the detergent box of thesecond washing drum, the water in the first washing drum is drained intothe second washing drum. If no, the water in the first washing drum isdrained into the second washing drum directly.

In step 2, when the water in the first washing drum is drained into thesecond washing drum, the height of the water level in the second washingdrum is detected. If the water level in the second washing drum reachesthe set water level value, there is water in the first washing drum, andthe remaining water of the first washing drum is discharged directly. Ifthe water in the first washing drum is entirely drained into the secondwashing drum, and the water level in the second washing drum does notreach the set water level value, then the second washing drum suppliesclean water through an external water inlet.

When the water in the first washing drum is drained away directly, it isdetermined whether or not the second washing drum is executing thedehydration process. If yes, the first washing drum waits until thedehydration process of the second washing drum is completed, and thendrains. If no, a time for reaching the dehydration process of the secondwashing drum is T₃₂, a time taken for the second washing drum todehydrate is T₃₃, an allowable waiting time T₃ is set. If T₃₂+T₃₃<T₃,the first washing drum waits until the dehydration process of the secondwashing drum is completed, and then drains. Otherwise, the water in thefirst washing drum is drained directly.

It is also possible to determine whether or not the water in the firstwashing drum can be reused by determining the washing state and thewashing times. In step 1, the water in the first washing drum cannot bereused, if the first washing drum is in a washing process when it drainsand the second washing drum is in a rinse process when it supplieswater; or if the first washing drum and the second washing drum are bothin the washing process when the first washing drum drains and the secondwashing drum supplies water, and a number of washing times of the firstwashing drum is less than a number of washing times of the secondwashing drum; or if the first washing drum and the second washing drumare both in the rinse process when the first washing drum drains and thesecond washing drum supplies water, and the number of rinsing times ofthe first washing drum is less than the number of rinsing times of thesecond washing drum.

When the second washing drum reaches the drainage process, it isdetermined whether or not the water in the second washing drum can bereused. If yes, comparing the time for reaching the water supply processof the first washing drum and the time for reaching the next drainageprocess of the second washing drum, it is determined whether or not thesecond washing drum waits until the first washing drum executes thewater supply process.

The drainage outlet of the first washing drum is communicated with thesecond washing drum, and the water in the first washing drum can bedrained into the second washing drum to reuse. The drainage outlet ofthe first washing drum is provided with a holding valve, the water inthe first washing drum can flow through the holding valve into thesecond washing drum. The second washing drum is provided with an inletvalve and the clean water can flow into the second washing drum throughthe inlet valve. The control method is as follows:

1) The first washing drum reaches the drainage process,

2) It is determined whether or not the water in the first washing drumcan be reused, if yes, execute step 3), if no, execute step 6),

3) A time T₁₁ for reaching a next drainage process of the first washingdrum, a time T₁₂ for reaching a water supply process of the secondwashing drum, if T₁₂<T₁₁, execute step 4), if T₁₂≧T₁₁, execute step 6),

4) The first washing drum waits until the second washing drum supplieswater, execute step 5),

5) The water in the first washing drum is drained into the secondwashing drum,

6) The water in the first washing drum is drained away directly.

The control method can also add a process of determining whether or notthe second washing drum is supplying water before comparing the time forreaching the next drainage process of the first washing drum and thetime for reaching executing the water supply process of the secondwashing drum. The control method is as follows:

1) The first washing drum reaches the drainage process,

2) It is determined whether or not the water in the first washing drumcan be reused, if yes, execute step 3), if no, execute step 7),

3) It is determined whether or not the second washing drum is executingthe water supply process, if no, execute step 4), if yes, execute step6),

4) It is determined a time T₁₁ for reaching a next drainage process ofthe first washing drum, a time T₁₂ for reaching a water supply processof the second washing drum, if T₁₂<T₁₁, execute step 5), if T₁₂≧T₁₁,execute step 7),

5) The first washing drum waits until the second washing drum supplieswater, execute step 6),

6) The water in the first washing drum is drained into the secondwashing drum,

7) The water in the first washing drum is drained away directly.

The control method may also include determining whether or not the firstwashing drum have enough time to wait the second washing drum supplyingwater, the control method is as follows:

1) The first washing drum reaches the drainage process,

2) It is determined whether or not the water in the first washing drumcan be reused, if yes, execute step 3), if no, execute step 8),

3) It is determined whether or not the second washing drum is executingthe water supply process, if no, execute step 4), if yes, execute step7),

4) It is determined a time T₁₁ for reaching a next drainage process ofthe first washing drum, a time T₁₂ for reaching a water supply processof the second washing drum, if T₁₂<T₁₁, execute step 5), if T₁₂≧T₁₁,execute step 8),

5) Set an allowable waiting time T₁, if T₁₂<T₁, execute step 6), ifT₁₂≧T₁, execute step 8),

6) The first washing drum waits until the second washing drum supplieswater, execute step 7),

7) The water in the first washing drum is drained into the secondwashing drum,

8) The water in the first washing drum is drained away directly.

If the water in the first washing drum is too dirty or water supplyprocess of the second washing drum is for the last rinse, the water inthe first washing drum cannot be reused as well. The control method isas follows:

1) The first washing drum reaches the drainage process,

2) The turbidity value or the bubble concentration value of the water inthe first washing drum is detected to determine whether or not theturbidity value or the bubble density value is smaller than the setvalue,

If yes, execute step 3), if no, execute step 9),

3) It is determined whether or not the second washing drum has only thelast rinse left, if no, execute step 4), if yes, execute step 9),

4) It is determined whether or not the second washing drum is executingwater supply process, if no, execute step 5), if yes, execute step 8),

5) It is determined a time T₁₁ for reaching a next drainage process ofthe first washing drum, a time T₁₂ for reaching a water supply processof the second washing drum, if T₁₂<T₁₁, execute step 6), if T₁₂≧T₁₁,execute step 9),

6) Set an allowable waiting time T₁, if T₁₂<T₁, execute step 7), ifT₁₂≧T₁, execute step 9),

7) The first washing drum waits until the second washing drum supplieswater, execute step 8),

8) The water in the first washing drum is drained into the secondwashing drum,

9) The water in the first washing drum is drained away directly.

When the water in the first washing drum is drained into the secondwashing drum and if the water supply of the second washing drum is forwashing, the detergent box need to be washed and water level need to bedetected. The control method is as follows:

1) The first washing drum reaches the drainage process,

2) The turbidity value or the bubble concentration value of the water inthe first washing drum is detected to determine whether or not theturbidity value or the bubble density value is smaller than the setvalue. If yes, execute step 3), if no, execute step 12),

3) It is determined whether or not the second washing drum has only thelast rinse left, if no, execute step 4), if yes, execute step 12),

4) It is determined whether or not the second washing drum is executingwater supply process, if no, execute step 5), if yes, execute step 10),

5) It is determined a time T₁₁ for reaching a next drainage process ofthe first washing drum, a time T₁₂ for reaching a water supply processof the second washing drum, if T₁₂<T₁₁, execute step 6), if T₁₂≧T₁₁,execute step 12),

6) Set an allowable waiting time T₁, if T₁₂<T₁, execute step 7), ifT₁₂≧T₁, execute step 12),

7) It is determined whether or not the second washing drum is executingthe water supply process for washing, if yes, execute step 8), if no,execute step 10),

8) The second washing drum first supplies water for washing thedetergent box, after the completion of water supply for washing thedetergent box of the second washing drum, execute step 9),

9) The first washing drum waits until the second washing drum supplieswater, execute step 10),

10) The water in the first washing drum is drained into the secondwashing drum,

11) Detect the height of the water level in the second washing drum.When the water level in the second washing drum reaches the set waterlevel value and if there is still water left in the first washing drum,the left water is drained away directly. If the water level in thesecond washing drum still not reaches the set water level value afterthe water in the first washing drum is entirely drained into the secondwashing drum, water from outside is flooded into the second washing drumthrough the water inlet.

12) The water in the first washing drum is drained away directly.

The first washing drum and the second washing drum of the presentembodiment are only for the sake of convenience of the description,regardless of the order of the relationship. It may also to reuse thewater in the second washing drum, the drainage outlet of the secondwashing drum is communicated with the first washing drum. The water inthe second washing drum can be drained into the first washing drum forreuse. The drainage outlet of the second washing drum is provided with aholding valve and the water in the second washing drum can flow into thefirst washing drum through the holding valve. The first washing drum isprovided with an inlet valve, clean water from outside can flow into thefirst washing drum through the inlet valve. When one washing drumreaches the drainage process, it is determined whether or not the waterof the washing drum is drained into the other washing drum for reuse.And when the other washing drum reaches the drainage process, it doesn'tneed to consider the water reuse of the other washing drum. It avoidscausing an infinite loop of both washing drums waiting. The controlmethod is as follows:

1) The second washing drum reaches the drainage process,

2) It is determined whether or not the water in the second washing drumcan be reused, if yes, execute step 3), if no, execute step 6),

3) It is determined a time T₁₁ for reaching a next drainage process ofthe second washing drum, a time T₁₂ for reaching a water supply processof the first washing drum, if T₁₂<T₁₁, execute step 4), if T₁₂≧T₁₁,execute step 6),

4) The second washing drum waits until the first washing drum supplieswater, execute step 5),

5) The water in the second washing drum is drained into the firstwashing drum,

6) The water in the second washing drum is drained away directly.

The control method can also add a process of determining whether or notthe first washing drum is supplying water before comparing the time forreaching the next drainage process of the second washing drum and thetime for reaching executing the water supply process of the firstwashing drum. The control method is as follows:

1) The second washing drum reaches the drainage process,

2) It is determined whether or not the water in the second washing drumcan be reused, if yes, execute step 3), if no, execute step 7),

3) It is determined whether or not the first washing drum is executingthe water supply process, if no, execute step 4), if yes, execute step6),

4) It is determined a time T₁₁ for reaching a next drainage process ofthe second washing drum, a time T₁₂ for reaching a water supply processof the first washing drum, if T₁₂<T₁₁, execute step 5), if T₁₂≧T₁₁,execute step 7),

5) The second washing drum waits until the first washing drum supplieswater, execute step 6),

6) The water in the second washing drum is drained into the firstwashing drum,

7) The water in the second washing drum is drained away directly.

The control method may also include determining whether or not thesecond washing drum have enough time to wait the first washing drumsupplying water, the control method is as follows:

1) The second washing drum reaches the drainage process,

2) It is determined whether or not the water in the second washing drumcan be reused, if yes, execute step 3), if no, execute step 8),

3) It is determined whether or not the first washing drum is executingthe water supply process, if no, execute step 4), if yes, execute step7),

4) It is determined a time T₁₁ for reaching a next drainage process ofthe second washing drum, a time T₁₂ for reaching a water supply processof the first washing drum, if T₁₂<T₁₁, execute step 5), if T₁₂≧T₁₁,execute step 8),

5) Set an allowable waiting time T₁, if T₁₂<T₁, execute step 6), ifT₁₂≧T₁, execute step 8),

6) The second washing drum waits until the first washing drum supplieswater, execute step 7),

7) The water in the second washing drum is drained into the firstwashing drum,

8) The water in the second washing drum is drained away directly.

If the water in the second washing drum is too dirty or water supplyprocess of the first washing drum is for the last rinse, the water inthe second washing drum cannot be reused. The control method is asfollows:

1) The second washing drum reaches the drainage process,

2) The turbidity value or the bubble concentration value of the water inthe second washing drum is detected to determine whether or not theturbidity value or the bubble concentration value is smaller than theset value,

if yes, execute step 3), if no, execute step 9),

3) It is determined whether or not the first washing drum has only thelast rinse left, if no, execute step 4), if yes, execute step 9),

4) It is determined whether or not the first washing drum is executingthe water supply process, if no, execute step 5), if yes, execute step8),

5) It is determined a time T₁₁ for reaching a next drainage process ofthe second washing drum, a time T₁₂ for reaching a water supply processof the first washing drum, if T₁₂<T₁₁, execute step 6), if T₁₂≧T₁₁,execute step 9),

6) Set an allowable waiting time T₁, if T₁₂<T₁, execute step 7), ifT₁₂≧T₁, execute step 9),

7) The second washing drum waits until the first washing drum supplieswater, execute step 8),

8) The water in the second washing drum is drained into the firstwashing drum,

9) The water in the second washing drum is drained away directly.

When the water in the second washing drum is drained into the firstwashing drum and if the water supply of the first washing drum is forwashing, the detergent box needs to be washed and water level needs tobe detected. The control method is as follows:

1) The second washing drum reaches the drainage process,

2) The turbidity value or the bubble concentration value of the water inthe second washing drum is detected to determine whether or not theturbidity value or the bubble concentration value is smaller than theset value. If yes, execute step 3), if no, execute step 12),

3) It is determined whether or not the first washing drum only has watersupply for the last rinse left, if no, execute step 4), if yes, executestep 12),

4) It is determined whether or not the first washing drum is executingany process, if no, execute step 5), if yes, execute step 10),

5) It is determined a time T₁₁ for reaching a next drainage process ofthe second washing drum, a time T₁₂ for reaching a water supply processof the first washing drum, if T₁₂<T₁₁, execute step 6), if T₁₂≧T₁₁,execute step 12),

6) Set an allowable waiting time T₁, if T₁₂<T₁, execute step 7), ifT₁₂≧T₁, execute step 12),

7) It is determined whether or not the first washing drum executes thewater supply process, if yes, execute step 8), if no, execute step 10),

8) The first washing drum first supplies water for washing the detergentbox, after the completion of water supply for washing the detergent boxof the first washing drum, execute step 9),

9) The second washing drum waits until the first washing drum supplieswater, execute step 10),

10) The water in the second washing drum is drained into the firstwashing drum,

11) Detect the height of the water level in the first washing drum. Whenthe water level in the first washing drum reaches the set water levelvalue and if there is still water left in the second washing drum, theleft water is drained away directly. If the water level in the firstwashing drum does still not reach the set water level value after thewater in the second washing drum is entirely drained into the firstwashing drum, water from outside is flooded into the first washing drumthrough the water inlet,

12) The water in the first washing drum is drained away directly.

Embodiment 4

As shown in FIG. 4, the present embodiment uses the waiting time of thewater supply as criterion to determine whether or not to reuse thewater. According to the waiting time of water supply, it is determinedwhether to reuse water drained from the other washing drum when onewashing drum reaches the water supply process. The method has a simplejudgment and control logic; the control stability is high in the actualwashing process. At the same time, it achieves a full reuse of water,and the practical value is high, which is more effective to promote andapply.

When the first washing drum and the second washing drum are both in theworking state at the same time, the control method of water reuse is asfollows:

A control method of water reuse of a multi-drum washing machine isprovided, and the multi-drum washing machine at least comprises a firstwashing drum and a second washing drum. When the first washing drum andthe second washing drum are both in the working state at the same time,the control method for water reuse is as follows: when the first washingdrum reaches the drainage process, it is compared a time T₂₂ forreaching a drainage process of the second washing drum and a time T₂₁for reaching a next water supply process of the first washing drum. IfT₂₂≧T₂₁, the first washing drum supplies clean water directly. IfT₂₂<T₂₁, the first washing drum waits until a start of the drainageprocess of the second washing drum.

It is determined whether or not the water in the second washing drum canbe reused before comparing the time T₂₂ for reaching the drainageprocess of the second washing drum and the time T₂₁ for reaching thenext water supply process of the first washing drum. If no, the water inthe first washing drum supplies clean water directly. If yes, it iscompared the time T₂₂ for reaching the drainage process of the secondwashing drum and the time T₂₁ for reaching the next water supply processof the first washing drum. Or, it is determined whether or not the waterin the second washing drum can be reused when the first washing drumwaits until the start of the drainage process of the second washingdrum. If no, the first washing drum supplies clean water directly. Ifyes, the water in the second washing drum is drained into the firstwashing drum for reuse.

Specific:

step 1: when the first washing drum reaches the water supply process, itis compared the time T₂₂ for reaching the drainage process of the secondwashing drum and the time T₂₁ for reaching the next water supply processof the first washing drum. If T₂₂≧T₂₁, the first washing drum suppliesclean water directly. If T₂₂<T₂₁, the first washing drum waits until astart of the drainage process of the second washing drum, execute step2;

Step 2: it is determined whether or not the water in the second washingdrum can be reused. If yes, the water in the second washing drum isdrained into the first washing drum to reuse, if no, the first washingdrum supplies clean water directly. By adding the process of thedetermination of whether or not to wait, to a large extent it increasesthe water reuse probability of the second washing drum, and more watercan be reused.

In step 1, if the second washing drum is draining water when the firstwashing drum reaches the water supply process, the time T₂₂ for reachingthe drainage process of the second washing drum is 0, and no need towait, and directly executes step 2. It is also possible to firstdetermine whether or not the second washing drum is currently executingthe drainage process before comparing the time T₂₂ for reaching thedrainage process of the second washing drum and the time T₂₁ forreaching the next water supply process of the first washing drum. If thesecond washing drum is not subjected to the drainage process, then it iscompared the time T₂₂ for reaching the drainage process of the secondwashing drum and the time T₂₁ for reaching the next water supply processof the first washing drum.

In step 1, an allowable waiting time T₂ is set, which T₂<T₂₁. If T₂₂<T₂,the first washing drum waits until the second washing drum drains, andexecutes step 2. If T₂₂≧T₂, the first washing drum supplies clean waterdirectly. This step can avoid the first washing drum waiting too longand reasonably arrange the water reuse under the premise of ensuring thewashing time of the first washing drum. Thus will not waste too muchtime of the first washing drum because of only considering water reuse.If the washing machine determines that the waiting time is too long andexceeds the set allowable waiting time, the first washing drum will notreuse the water in the second washing drum. The determination makes thereuse of water more reasonable, optimizing the relationship betweenwaiting time and water reuse.

In step 2, the turbidity value or the bubble concentration value of thewater in the second washing drum is detected. If the turbidity value orthe bubble concentration value of the water is smaller than the setvalue, the water in the second washing drum can be reused. Otherwise thewater in the second washing drum cannot be reused. Water can be reusedwhen the turbidity value or bubble concentration value of the water iswithin the set range.

In step 1, when the first washing drum reaches the drainage process, itis determined whether or not the water supply process being executed isa water supply for a last rinse. If yes, the first washing drum suppliesclean water directly. If no, it is continued to compare the time T₂₂ forreaching the drainage process of the second washing drum and the timeT₂₁ for reaching the next water supply process of the first washingdrum. Thus it is ensured that the water supplied-in in the last rinseprocess is clean water, which ensures that the effect of washing clothesafter washing.

In step 2, when the water in the second washing drum is drained into thefirst washing drum, it is determined whether or not the first washingdrum executes the water supply process for washing. If yes, the firstwashing drum first supplies water for washing the detergent box. Afterthe completion of water supply for washing the detergent box of thefirst washing drum, the water in the second washing drum is drained intothe first washing drum. If no, the water in the second washing drum isdrained into the first washing drum directly.

In step 2, when the water in the second washing drum is drained into thefirst washing drum, the height of the water level in the first washingdrum is detected. If the water level in the first washing drum reachesthe set water level value, there is water in the second washing drum,and the remaining water in the second washing tub is dischargeddirectly. If the water in the second washing drum is entirely drainedinto the first washing drum, and the water level in the first washingtub does not reach the set water level value, then the first washingdrum supplies clean water.

When the water in the second washing drum is drained away directly, itis determined whether or not the first washing drum is executing thedehydration process. If yes, the second washing drum waits until thedehydration process of the first washing drum is completed, and thendrains. If no, it is determined a time for reaching the dehydrationprocess of the first washing drum is T₄₁, a time taken for the firstwashing drum to dehydrate is T₄₄, and an allowable waiting time T₄ isset. If T₄₁+T₄₄<T₄, the second washing drum waits until the dehydrationprocess of the first washing drum is completed, and then drains.Otherwise, the water of the second washing drum is drained directly.

It is also possible to determine whether or not the water in the firstwashing drum can be reused by determining the washing state and thewashing times. In step 2, the water in the first washing drum cannot bereused, if the second washing drum is in a washing process when itdrains and the first washing drum is in a rinse process when it supplieswater; or if the first, second washing drums are both in the washingprocess when the second washing drum drains and the first washing drumsupplies water, and washing times of the second washing drum is lessthan washing times of the first washing drum; or if the first, secondwashing drums are both in the rinse process when the second washing drumdrains and the first washing drum supplies water, and washing times ofthe second washing drum is less than washing times of the first washingdrum.

When the second washing drum reaches the water supply process, it iscompared the time for reaching the drainage process of the first washingdrum and the time for reaching the next water supply of the secondwashing drum, it is determined whether or not the second washing drumwaits until the first washing drum drains.

The drainage outlet of the second washing drum is communicated with thefirst washing drum, and the water in the second washing drum can bedrained into the first washing drum to reuse. The drainage outlet of thesecond washing drum is provided with a holding valve, the water in thesecond washing drum can flow through the holding valve into the firstwashing drum. The first washing drum is provided with an inlet valve andthe clean water can flow into the first washing drum through the inletvalve. The control method is as follows:

1) The first washing drum reaches the water supply process,

2) It is determined whether or not the water in the second washing drumcan be reused, if yes, execute step 3), if no, execute step 6),

3) It is determined a time T₂₁ for reaching a next water supply processof the first washing drum, a time T₂₂ for reaching a drainage process ofthe second washing drum, if T₂₂<T₂₁, execute step 4), if T₂₂≧T₂₁,execute step 6),

4) The first washing drum waits until the second washing drum drains,execute step 5),

5) The water in the second washing drum is drained into the firstwashing drum,

6) The first washing drum supplies clean water directly and the water inthe second washing drum is drained away directly.

The control method can also add a process of determining whether or notthe second washing drum is draining water before comparing the time T₂₂for reaching the drainage process of the second washing drum and thetime T₂₁ for reaching the next water supply process of the first washingdrum. The control method is as follows:

1) The first washing drum reaches the water supply process,

2) It is determined whether or not the water in the second washing drumcan be reused, if yes, execute step 3), if no, execute step 7),

3) It is determined whether or not the second washing drum is executingthe drainage process, if no, execute step 4), if yes, execute step 6),

4) It is determined a time T₂₁ for reaching a next water supply processof the first washing drum, a time T₂₂ for reaching a drainage process ofthe second washing drum, if T₂₂<T₂₁, execute step 5), if T₂₂≧T₂₁,execute step 7),

5) The first washing drum waits until the second washing drum drains,executes step 6),

6) The water in the second washing drum is drained into the firstwashing drum,

7) The first washing drum supplies clean water directly and the water inthe second washing drum is drained away directly.

The control method may also include determining whether or not the firstwashing drum has enough time to wait the second washing drum draining,the control method is as follows:

1) The first washing drum reaches the water supply process,

2) It is determined whether or not the water in the second washing drumcan be reused, if yes, execute step 3), if no, execute step 8),

3) It is determined whether or not the second washing drum is executingthe drainage process, if no, execute step 4), if yes, execute step 7),

4) It is determined a time T₂₁ for reaching a next water supply processof the first washing drum, a time T₂₂ for reaching a drainage process ofthe second washing drum, if T₂₂<T₂₁, execute step 5), if T₂₂≧T₂₁,execute step 8),

5) an allowable waiting time T₂ is set, if T₂₂<T₂, execute step 6), ifT₂₂≧T₂, execute step 8),

6) The first washing drum waits until the second washing drum drains,execute step 7),

7) The water in the second washing drum is drained into the firstwashing drum,

8) The first washing drum supplies clean water directly and the water inthe second washing drum is drained away directly.

If the water in the second washing drum is too dirty or water supplyprocess of the first washing drum is for the last rinse, the water inthe second washing drum cannot be reused. The control method is asfollows:

1) The first washing drum reaches the water supply process,

2) It is determined whether or not the first washing drum has only thelast rinse left, if no, execute step 3), if yes, execute step 9),

3) It is determined whether or not the second washing drum is executingdrainage process, if no, execute step 4), if yes, execute step 7),

4) It is determined a time T₂₁ for reaching a next water supply processof the first washing drum, a time T₂₂ for reaching a drainage process ofthe second washing drum, if T₂₂<T₂₁, execute step 5), if T₂₂≧T₂₁,execute step 9),

5) an allowable waiting time T₂ is set, if T₂₂<T₂, execute step 6), ifT₂₂≧T₂, execute step 9),

6) The first washing drum waits until the second washing drum supplieswater, execute step 7),

7) The turbidity value or the bubble concentration value of the water inthe second washing drum is detected to determine whether or not theturbidity value or the bubble density value is smaller than the setvalue, If yes, execute step 8), if no, execute step 9),

8) The water in the second washing drum is drained into the firstwashing drum,

9) The first washing drum supplies clean water directly and the water inthe second washing drum is drained away directly.

When the water in the second washing drum is drained into the firstwashing drum and if the water supply of the first washing drum is forwashing, the detergent box need to be washed and water level need to bedetected. The control method is as follows:

1) The first washing drum reaches the water supply process,

2) It is determined whether or not the first washing drum has only thelast rinse left, if no, execute step 3), if yes, execute step 12),

3) It is determined whether or not the second washing drum is executingdrainage process, if no, execute step 4), if yes, execute step 7),

4) It is determined a time T₂₁ for reaching a next water supply processof the first washing drum, a time T₂₂ for reaching a drainage process ofthe second washing drum, if T₂₂<T₂₁, execute step 5), if T₂₂≧T₂₁,execute step 12),

5) An allowable waiting time T₂ is set, if T₂₂<T₂, execute step 6), ifT₂₂≧T₂, execute step 12),

6) The first washing drum waits until the second washing drum drainswater, execute step 7),

7) The turbidity value or the bubble concentration value of the water inthe second washing drum is detected to determine whether or not theturbidity value or the bubble density value is smaller than the setvalue,

if yes, execute step 8), if no, execute step 12),

8) It is determined whether or not the first washing drum is executingthe water supply process for washing, if yes, execute step 9), if no,execute step 10),

9) The first washing drum first supplies water for washing the detergentbox, after the completion of water supply for washing the detergent boxof the first washing drum, execute step 10),

10) The water in the second washing drum is drained into the firstwashing drum,

11) It is detected the height of the water level in the first washingdrum. When the water level in the first washing drum reaches the setwater level value and if there is still water left in the second washingdrum, the left water is drained away directly. If the water level in thefirst washing drum still not reaches the set water level value after thewater in the second washing drum is entirely drained into the firstwashing drum, water from outside is flooded into the first washing drumthrough the water inlet.

12) The first washing drum supplies clean water directly and the waterin the second washing drum is drained away directly.

The first washing drum and the second washing drum of the presentembodiment are only for the sake of convenience of the description,regardless of the order of the relationship. It may also to reuse thewater in the first washing drum, the water inlet of the second washingdrum is communicated with the drainage outlet of the first washing drum.The water in the first washing drum can be drained into the secondwashing drum for reuse. The drainage outlet of the first washing drum isprovided with a holding valve and the water of the first washing drumcan flow into the second washing drum through the holding valve. Thesecond washing drum is provided with a water inlet, clean water fromoutside can flow into the second washing drum through the water inlet.When one washing drum reaches the water supply process, it is determinedwhether or not the water in the other washing drum is drained into thewashing drum for reuse. And when the other washing drum reaches thewater supply process, it doesn't need to consider the water reuse of thewashing drum. It avoids causing an infinite loop of both washing drumswaiting.

The control method is as follows:

1) The second washing drum reaches the water supply process,

2) It is determined whether or not the water in the first washing drumcan be reused, if yes, execute step 3), if no, execute step 6),

3) It is determined a time T₂₁ for reaching a next water supply processof the second washing drum, a time T₂₂ for reaching a drainage processof the first washing drum, if T₂₂<T₂₁, execute step 4), if T₂₂≧T₂₁,execute step 6),

4) The second washing drum waits until the first washing drum drains,execute step 5),

5) The water in the first washing drum is drained into the secondwashing drum,

6) The second washing drum supplies clean water directly and the waterin the first washing drum is drained away directly.

The control method can also add a process of determining whether or notthe first washing drum is draining before comparing the time T₂₂ forreaching the next drainage process of the second washing drum and thetime T₂₁ for reaching executing the next water supply process of thefirst washing drum. The control method is as follows:

1) The second washing drum reaches the water supply process,

2) It is determined whether or not the water in the first washing drumcan be reused, if yes, execute step 3), if no, execute step 7),

3) It is determined whether or not the first washing drum is executingthe drainage process, if no, execute step 4), if yes, execute step 6),

4) It is determined a time T₂₁ for reaching a next water supply processof the second washing drum, a time T₂₂ for reaching a drainage processof the first washing drum, if T₂₂<T₂₁, execute step 5), if T₂₂≧T₂₁,execute step 7),

5) The second washing drum waits until the first washing drum drains,execute step 6),

6) The water in the first washing drum is drained into the secondwashing drum,

7) The second washing drum supplies clean water directly and the waterin the first washing drum is drained away directly.

The control method may also include determining whether or not thesecond washing drum has enough time to wait the first washing drum todrain, the control method is as follows:

1) The second washing drum reaches the water supply process,

2) It is determined whether or not the water in the first washing drumcan be reused, if yes, execute step 3), if no, execute step 8),

3) It is determined whether or not the first washing drum is executingthe drainage process, if no, execute step 4), if yes, execute step 7),

4) It is determined a time T₂₁ for reaching a next water supply processof the second washing drum, a time T₂₂ for reaching a drainage processof the first washing drum, if T₂₂<T₂₁, execute step 5), if T₂₂≧T₂₁,execute step 8),

5) An allowable waiting time T₂ is set, if T₂₂<T₂, execute step 6), ifT₂₂≧T₂, execute step 8),

6) The second washing drum waits until the first washing drum drains,execute step 7),

7) The water in the first washing drum is drained into the secondwashing drum,

8) The second washing drum supplies clean water directly and the waterin the first washing drum drains away directly.

If the water in the first washing drum is too dirty or water supplyprocess of the second washing drum is for the last rinse, the water inthe first washing drum cannot be reused. The control method is asfollows:

1) The second washing drum reaches the water supply process,

2) It is determined whether or not the second washing drum has only thelast rinse left, if yes, execute step 3), if no, execute step 9),

3) It is determined whether or not the first washing drum is executingthe drainage process, if no, execute step 4), if yes, execute step 7),

4) It is determined a time T₂₁ for reaching a next water supply processof the second washing drum, a time T₂₂ for reaching a drainage processof the first washing drum, if T₂₂<T₂₁, execute step 5), if T₂₂≧T₂₁,execute step 9),

5) An allowable waiting time T₂ is set, if T₂₂<T₂, execute step 6), ifT₂₂≧T₂, execute step 9),

6) The second washing drum waits until the first washing drum drains,execute step 7),

7) The turbidity value or the bubble concentration value of the water inthe first washing drum is detected to determine whether or not theturbidity value or the bubble density value is smaller than the setvalue. If yes, execute step 8), if no, execute step 9),

8) The water in the first washing drum is drained into the secondwashing drum,

9) The second washing drum supplies clean water directly and the waterin the first washing drum is drained away directly.

When the water of the first washing drum is drained into the secondwashing drum and if the water supply of the second washing drum is forwashing, the detergent box need to be washed and water level need to bedetected. The control method is as follows:

1) The second washing drum reaches the water supply process,

2) It is determined whether or not the second washing drum only haswater supply for the last rinse left, if no, execute step 3), if yes,execute step 12),

3) It is determined whether or not the first washing drum is executingthe drainage process, if no, execute step 4), if yes, execute step 7),

4) It is determined a time T₂₁ for reaching a next water supply processof the second washing drum, a time T₂₂ for reaching a drainage processof the first washing drum, if T₂₂<T₂₁, execute step 5), if T₂₂≧T₂₁,execute step 12),

5) An allowable waiting time T₂ is set, if T₂₂<T₂, execute step 6), ifT₂₂≧T₂, execute step 12),

6) The second washing drum waits until the first washing drum drains,execute step 7),

7) The turbidity value or the bubble concentration value of the water inthe first washing drum is detected to determine whether or not theturbidity value or the bubble density value is smaller than the setvalue,

if yes, execute step 8), if no, execute step 12),

8) It is determined whether or not the second washing drum is executingthe water supply process for washing, if yes, execute step 9), if no,execute step 10),

9) The second washing drum first supplies water for washing thedetergent box,

after the completion of water supply for washing the detergent box ofthe second washing drum, execute step 10),

10) The water in the first washing drum is drained into the secondwashing drum,

11) It is detected the height of the water level in the second washingdrum. When the water level in the second washing drum reaches the setwater level value and if there is still water left in the first washingdrum, the left water is drained away directly. If the water level in thesecond washing drum still not reaches the set water level value afterthe water in the first washing drum is entirely drained into the secondwashing drum, water from outside is flooded into the second washing drumthrough the water inlet,

12) The second washing drum supplies clean water directly and the waterin the first washing drum is drained away directly.

While there has been shown several and alternate embodiments of thepresent disclosure, it is to be understood that various of variants andimprovement can be made as would be known to one skilled in the artwithout departing from the underlying scope of the present invention asis discussed and set forth above and below including claims.

1. A drainage control method of a multi-drum washing machine which atleast comprises a first washing drum and a second washing drum, wherein:when the first washing drum reaches a drainage process, it is determinedwhether or not the second washing drum is in a dehydration process atthis time, if the second washing drum is in the dehydration process, thefirst washing drum waits until the dehydration process of the secondwashing drum is completed, and then drains; if the second washing drumis not in the dehydration process at this time, it is determined whetheror not the first washing drum waits until the dehydration process of thesecond washing drum is completed, and then drains.
 2. The drainagecontrol method of the multi-drum washing machine according to claim 1,wherein: the process to determine whether or not the first washing drumwaits until the dehydration process of the second washing drum iscompleted and then drains includes: determining a time T₃₂ for reachingthe dehydration process of the second washing drum and a time T₃₃ takenfor the second washing drum to dehydrate is, and setting an allowablewaiting time T₃, if T₃₂+T₃₃<T₃, the first washing drum waiting until thedehydration process of the second washing drum is completed, and thendraining, otherwise, water in the first washing drum being draineddirectly.
 3. The drainage control method of the multi-drum washingmachine according to claim 1, wherein: when the first washing reachesthe drainage process, it is determined whether or not the second washingdrum is draining at this time, if the second washing drum is draining atthe time, the first washing drum waits until a drainage of the secondwashing drum is completed, and drains, otherwise, the water in the firstwashing drum is drained directly.
 4. The drainage control method of themulti-drum washing machine according to claim 1, wherein: when the firstwashing drum reaches the drainage process, it is compared a time T₁₂ forreaching a water supply process of the second washing drum and a timeT₁₁ for reaching a next drainage process of the first washing drum, ifT₁₂<T₁₁, the first washing drum waits until the second washing drumsupplies water, if T₁₂≧T₁₁, the water in the first washing drum isdrained directly.
 5. The drainage control method of the multi-drumwashing machine according to claim 4, wherein: it is determined whetheror not the water in the first washing drum can be reused beforecomparing the time T₁₂ for reaching the water supply process of thesecond washing drum and the time T₁₁ for reaching the next drainageprocess of the first washing drum, if no, the water in the first washingdrum is drained directly, if yes, it is compared the time T₁₂ forreaching the water supply process of the second washing drum and thetime T₁₁ for reaching the next drainage process of the first washingdrum; or, it is determined whether or not the water in the first washingdrum is reused when the first washing drum waits until the secondwashing drum supplies water, if no, the water in the first washing drumis drained directly, if yes, the water in the first washing drum isdrained into the second washing drum for reusing.
 6. The drainagecontrol method of the multi-drum washing machine according to claim 4,wherein: if the second washing drum is supplying water when the firstwashing drum reaches the drainage process, the time T₁₂ for reaching thewater supply process of the second washing drum is 0, and no need towait.
 7. The drainage control method of the multi-drum washing machineaccording to claim 4 wherein: an allowable waiting time T₁ is set,T₁<T₁₁, it is compared the time T₁₂ for reaching the water supplyprocess of the second washing drum and the allowable waiting time T₁, ifT₁₂<T₁, the first washing drum waits until the second washing drumsupplies water, if T₁₂≧T₁, the water in the first washing drum isdrained directly.
 8. The drainage control method of the multi-drumwashing machine according to claim 4 wherein: when the first washingdrum reaches the drainage process, it is determined whether or not theprocess which the second washing drum is in progress or is about to beperformed is a water supply for a last rinse, if yes, the water in thefirst washing drum is drained directly, if no, it is continued to bedetermined whether or not the water in the first washing drum can bereused.
 9. The drainage control method of the multi-drum washing machineaccording to claim 1 wherein: when the second washing drum reaches thedrainage process, it is determined whether or not the first washing drumis in the dehydration process at this time, if the first washing drum isin the dehydration process, the second washing drum waits until thedehydration process of the first washing drum is completed, and thendrains, if the first washing drum is not in the dehydration process atthis time, it is determined whether or not to wait until the dehydrationprocess of the first washing drum is completed, and then drains.
 10. Thedrainage control method of the multi-drum washing machine according toclaim 1 wherein: when the first washing drum reaches the drainageprocess, it is determined whether or not the second washing drum isoperating at this time, if yes, it is determined whether or not thesecond washing drum is in the dehydration process or is about to executethe dehydration process, if no, the first washing drum directly executesthe drainage process.
 11. A drainage control method of a multi-drumwashing machine which at least comprises a first washing drum and asecond washing drum, wherein: when the first washing drum reaches adrainage process, it is determined whether or not the second washingdrum is in a drainage process or in a dehydration process, if the secondwashing drum is in the drainage process or in the dehydration process,the first washing drum waits until the dehydration process of the secondwashing drum is completed, and then drains; if the second washing drumis not in the drainage process or in the dehydration process, it isdetermined whether or not the first washing drum needs to wait until thedehydration process of the second washing drum is completed, and thendrains.
 12. The drainage control method of the multi-drum washingmachine according to claim 11, wherein: a process for determiningwhether or not the first washing drum needs to wait until thedehydration process of the second washing drum is completed, and thendrains, comprises, determining T₃₁ a time for reaching the drainageprocess of the second washing drum, a time T₃₄ taken for the secondwashing drum to drain, a time T₃₃ taken for the second washing drum todehydrate, and a time T₅ for reaching a next drainage process of thefirst washing drum, if T₅<T₃₁+T₃₄, the water in the first washing drumbeing drained directly, otherwise, continuing to be determined whetheror not the first washing drum needs to wait until the dehydrationprocess of the second washing drum is completed, and then drains. 13.The drainage control method of the multi-drum washing machine accordingto claim 11, wherein: a process for determining whether or not the firstwashing drum needs to wait until the dehydration process of the secondwashing drum is completed, and then drains, comprises determining thetime T₃₁ for reaching the drainage process of the second washing drum,the time T₃₄ taken for the second washing drum to drain, and the timeT₃₃ taken for the second washing drum to dehydrate, setting an allowablewaiting time T₃, if T₃₁+T₃₄+T₃₃<T₃, the first washing drum waiting untilthe dehydration process of the second washing drum is completed, andthen draining, otherwise, the water in the first washing drum beingdrained directly.
 14. The drainage control method of the multi-drumwashing machine according to claim 11, wherein: when the first washingdrum reaches the drainage process, it is firstly determined whether ornot the second washing drum is operating, if no, the first washing drumdirectly executes the drainage process, if yes, it is continued to bedetermined whether or not the second washing drum is in the drainageprocess or in the dehydration process.
 15. The drainage control methodof the multi-drum washing machine according to claim 11, wherein: if itis determined the first washing drums waits until the dehydrationprocess of the second washing drum is completed, it is determinedwhether or not the second washing drum needs to supply water after thedehydration process is completed, if water supply is not required, thewater in the first washing drum is drained directly, if water supply isrequired, it is determined whether or not the water in the first washingdrum can be reused, if the water can be reused, the water in the firstwashing drum is drained into the second washing drum.
 16. The drainagecontrol method of the multi-drum washing machine according to claim 11,wherein: when the first washing drum reaches the drainage process and ifthe second washing drum is supplying water, it is determined whether ornot the water in the first washing drum can be reused, if the water canbe reused, the water in the first washing drum is drained into thesecond washing drum.
 17. The drainage control method of the multi-drumwashing machine according to claim 15, wherein: if the process whichsecond washing drum is in or is about to perform is a water supply for alast rinse, the water in the first washing drum cannot be reused. 18.The drainage control method of the multi-drum washing machine accordingto claim 15, wherein: if the first washing drum is in a drainage of alast rinse, the water in the first washing drum cannot be reused. 19.The drainage control method of the multi-drum washing machine accordingto claim 15, wherein: the water in the first washing drum cannot bereused, if the first washing drum is in a washing process when itdrains, and the second washing drum is in a rinse process when itsupplies water; or if the first and second washing drums are both in thewashing process when the first washing drum drains and the secondwashing drum supplies water, and washing times of the first washing drumis less than washing times of the second washing drum; or if the firstand second washing drums are both in the rinse process when the firstwashing drum drains and the second washing drum supplies water, andrinsing times of the first washing drum is less than rinsing times ofthe second washing drum; or if a turbidity of the water in the firstwashing drum exceeds a set value.
 20. The drainage control method of themulti-drum washing machine according to claim 11, wherein: when thesecond washing drum reaches the drainage process, it is determinedwhether or not the first washing drum is in the drainage process or inthe dehydration process at this time, if the first washing drum is inthe drainage process or in the dehydration process, the second washingdrum waits until the dehydration of the first washing drum is completed,and then drains, if the first washing drum is not in the drainageprocess or in the dehydration process, it is determined whether or notthe second washing drum needs to wait until the dehydration process ofthe first washing drum is completed, and then drains.